Spaceflight Insider

Turning it up to 11: Atlas V to launch pair of AFSPC-11 satellites for US Air Force

A file photo of a previous Atlas V 551 launch. The AFSPC-11 mission is set to lift off in the evening of April 14, 2018. Photo Credit: United Launch Alliance

A file photo of a previous Atlas V 551 launch. The AFSPC-11 mission is set to lift off in the evening of April 14, 2018. Photo Credit: United Launch Alliance

CAPE CANAVERAL, Fla. — Ground crews are making ready a United Launch Alliance (ULA) Atlas V rocket to loft two primary U.S. Air Force payloads into geosynchronous orbit for the Air Force Space Command 11 (AFSPC-11) mission.

According to ULA, the Atlas V is set to liftoff a 7:13 p.m. EDT (11:13 GMT) April 14, 2018, from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida.

The payload

Sitting atop the 191-foot (58.3-meter) tall Atlas V are two Air Force primary payloads: the Continuous Broadcast SATCOM (CBAS) and the Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA) Augmented Geosynchronous Laboratory Experiment (EAGLE). EAGLE has the capability of hosting up to six secondary satellites, each weighing up to 400 pounds (181.44 kilograms).

Mission logo for AFSPC-11, with the Atlas V pointed to the '11' spot on the dial as a reference from 'This is Spinal Tap'. Image credit: U.S. Air Force

Mission logo for AFSPC-11, with the Atlas V pointed to the ’11’ spot on the dial as a reference from ‘This is Spinal Tap’. Image Credit: U.S. Air Force

Though classified, the two innocuous-sounding payloads seem to have piqued the interest of ULA President and CEO Tory Bruno.

“Completed the President’s Mission Readiness Review for AFSPC11. Clean bird. Everything about this one is interesting. Too bad I can’t tell you anything about it…,” tweeted Bruno.

While little is publicly known about either passenger, some information has been gleaned through official postings, and on industry websites.

CBAS, situated in the upper position of the payload fairing, is meant to supplement military communications by continuously broadcasting data through existing satellite comms relay links.

EAGLE, taking the lower slot on this multi-manifested mission, appears to be the interesting hardware on the flight. According to information at Gunter’s Space Page, EAGLE should host five secondary payloads: the Hypertemporal Imaging Space Experiment (HTI-SpX), MYCROFT, the Compact Environmental Anomaly Sensor III Risk Reduction (CEASE-III-RR), the Inverse Synthetic Aperture Ladar (ISAL), and the AFRL-1201 Resilient Spacecraft Bus Development Experiment (ARMOR).

Though the secondary payloads are shrouded in as much secrecy as the rest of the hardware on the mission, some information has been published.

HTI-SpX is designed to advance the understanding of blended images of various locations, sourced from disparate wavelengths, taken over time. ISAL, on the other hand, seems to be focused in different direction. The secondary payload will likely use its imaging capabilities to take a peek at objects in geosynchronous earth orbit.

The Rocket

Tasked with launching the classified mission is the Atlas V in its “551” configuration—the most powerful variant of ULA’s workhorse rocket. The “551” designation signifies a 5-meter payload fairing, five supplemental Aerojet Rocketdyne AJ-60A solid rocket boosters, provide nearly 1.9 million pounds (8,442 kilonewtons) of combined thrust during their 94-second burn time. Finally, a single RL10C-powered Centaur stage (also produced by Aerojet Rocketdyne) helps provide the thrust required to complete the spacecraft’s journey.

“The Atlas V is able to perform a wide variety of missions for both government and commercial customers, and the AJ-60A is a major factor in that versatility,” said Aerojet Rocketdyne CEO and President Eileen Drake via a company-issued release. “Aerojet Rocketdyne developed the AJ-60A specifically for the Atlas V, delivering the first booster just 42 months after the contract award, which underscores our team’s ability to design and deliver large solid rocket motors in support of our nation’s strategic goals and efforts to explore our solar system.”

The Atlas common booster core is powered by a Russian-made RD-180 main engine, which provides an estimated 860,000 pounds (3,827 kilonewtons) of thrust at liftoff. This increases to 933,000 pounds (4,152 kilonewtons) as the vehicle climbs and the atmosphere thins.

Burning a mixture of rocket grade kerosene (known as RP-1) and liquid oxygen, the RD-180 has been a reliable powerplant for ULA’s rocket with the notable exception of an anomaly on the OA-6 resupply mission to the International Space Station.

The Atlas V’s second, or Centaur, stage is outfitted with a single Aerojet Rocketdyne RL10C. The RL10 family has a long history, with a heritage dating back to the 1950s and its first flight taking place in 1961. The RL10C-1 model flown on the Atlas V Centaur provides some 22,890 pounds (101.8 kilonewtons) of ‘vacuum’ thrust and has been solidly dependable throughout its use on the Atlas V, save for an issue on the NROL-30 mission.

Like its OA-6 counterpart, the NROL-30 mission was still classified as a success as the payload was able to reach its intended orbit. Those aberrations aside, the Atlas V has proven itself to be a highly-dependable launch vehicle with a 100 percent mission success rate.

AFSPC-11 will mark the eighth flight of the Atlas V 551, and the 77th overall for a member of the Atlas V line. SpaceFlight Insider will host a Live Webcast covering the launch.

Video courtesy of United Launch Alliance





Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

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